Lobster Aquaculture in Panama
In the beginning of October, 2015, live juvenile lobsters (Panulirus gracilis) were purchased from a local fisherman at 10.3 g average weight and stocked into a zero water exchange system. Over the course of the next 7 months lobsters were fed various prepared and raw feeds and average weights and feed conversion ratios (FCR) were calculated monthly with widely varying results of 2 to 43. Although mostly proteins are widely consumed in the wild, there were vast differnces in FCRs, meaning that these lobsters can digest and assimilate marine proteins differenty. Lobsters weighed only 27 g at the end of four months with regular mortality of 3-6% per month. Runts were typically culled out by cohorts, as the sizes of lobsters became more uniform.
From 20-May-16 to 8-Sept-16, survivals were 100% and water quality in the closed system was near perfect. Growth, FCRs and % increase in biomass varied from month to month as different combinations of feeds were offered (see table below). As of 10-Sept-16 biomass was up to 4.3 kg/m3, with lobsters reaching 137 g on average (picture right).
The diet for lobsters during 8-Sept to 10-Oct was radically changed which produced 1/2 of the growth of the previous month. Some wasted feed was found during sampling and NO2 in the system had increased from 0.5 to 2.5 during the week before sampling. A single lobster was found that was gray in color and had a bacterial disease which was apparent on the tail as an open sore (photo right). Survivals were still 100%. Nitrite in the system was quickly reduced in 24hrs wtih a contingency treatment used previously in other systems.
Picture at lower right shows sexual dimorphism for this species in pleopod shape.
This is not only the first time this lobster species has been grown in an aquaculture system but the first time in a zero water exchange system as well.
Growth for the previous month was 6.1 g/wk which is 2x of the average of the previous 3 months. Mortalities increased due to bacterial infection which was evident from sampling as so a new protocol will be used. Lobsters reached 1/2 lb as of this sampling date (pic right) with biomass > 5 kg/m3.